[EC] Unify point doubling for P-256/384/521

[dkostic]

Issues:

CryptoAlg-2408

Description of changes:

Implement and use a single version of point doubling
for implementations of NIST curves P-384, P-521, and
Fiat-crypto based implementation of P-256. The change
does not affect performance.

Point addition will be unified in a subsequent change.

Call-outs:

I verified the performance was not affected on Graviton 3, Intel, and M1 CPUs. Example for M1:

Before
Did 2882750 EC POINT P-384 dbl operations in 1000082us (2882513.6 ops/sec)
Did 1600000 EC POINT P-384 add operations in 1000497us (1599205.2 ops/sec)
Did 7051 EC POINT P-384 mul operations in 1078289us (6539.1 ops/sec)
Did 28000 EC POINT P-384 mul base operations in 1000115us (27996.8 ops/sec)
Did 5632 EC POINT P-384 mul public operations in 1062456us (5300.9 ops/sec)
Did 2685500 EC POINT P-521 dbl operations in 1000037us (2685400.6 ops/sec)
Did 1435000 EC POINT P-521 add operations in 1000129us (1434814.9 ops/sec)
Did 4928 EC POINT P-521 mul operations in 1055318us (4669.7 ops/sec)
Did 19000 EC POINT P-521 mul base operations in 1022199us (18587.4 ops/sec)
Did 3850 EC POINT P-521 mul public operations in 1036809us (3713.3 ops/sec)

After:
Did 2888250 EC POINT P-384 dbl operations in 1000028us (2888169.1 ops/sec)
Did 1593000 EC POINT P-384 add operations in 1000405us (1592355.1 ops/sec)
Did 6875 EC POINT P-384 mul operations in 1054301us (6520.9 ops/sec)
Did 28000 EC POINT P-384 mul base operations in 1000818us (27977.1 ops/sec)
Did 5555 EC POINT P-384 mul public operations in 1056370us (5258.6 ops/sec)
Did 2775250 EC POINT P-521 dbl operations in 1000021us (2775191.7 ops/sec)
Did 1435000 EC POINT P-521 add operations in 1000085us (1434878.0 ops/sec)
Did 4840 EC POINT P-521 mul operations in 1044164us (4635.3 ops/sec)
Did 19000 EC POINT P-521 mul base operations in 1027887us (18484.5 ops/sec)
Did 3883 EC POINT P-521 mul public operations in 1051447us (3693.0 ops/sec)

Testing:

How is this change tested (unit tests, fuzz tests, etc.)? Are there any testing steps to be verified by the reviewer?

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and the ISC license.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.92%. Comparing base (7ef93cb) to head (4b55dad).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1567   +/-   ##
=======================================
  Coverage   77.91%   77.92%           
=======================================
  Files         560      561    +1     
  Lines       94629    94620    -9     
  Branches    13620    13599   -21     
=======================================
  Hits        73729    73729           
+ Misses      20305    20299    -6     
+ Partials      595      592    -3     

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